In underground potash and comparable evaporite mines, conventional mining operations typically engage extensive ore extraction and transportation equipment, and highly skilled personnel. Boring machines cut and move the ore away from the mining faces. The extracted ore is conveyed to the vicinity of the mine shaft and then hoisted to surface in open-topped containers called skips.
The tonnages and depths from which evaporite ores are hoisted typically require many years to construct and significant capital investment. In Saskatchewan, for example, potash ore hoisting is typically accomplished through concrete lined shafts 16 ft or more in diameter and approximating 3,000 ft deep. The shafts are fitted with about 200 ft-300 ft high headframes required to deflect the hoist ropes and house ancillary equipment. The hoists or winders utilized to raise and lower the skips are approximately 20 ft in diameter and have a hoist motor nominal of 10,000 kW.
It is a challenging problem to increase, on an incremental basis, the output from a mine that has reached or is approaching its maximum mechanical/electrical hoisting capacity. In such cases, increasing mine output would normally require construction and operation of another mine shaft at a very high cost. Operators must pay not only the costs of additional underground equipment and personnel, but also the large ultimately sunk capital cost of the hoisting plant. The cost of the hoisting plant is often a significant drawback to increasing mine production because it is both a large potential capacity increase in the hoisting rate and a prohibitive capital cost.
This and other drawbacks associated with conventionally-sought approaches to increasing the hoisting rate of underground mines are addressed by the methods disclosed herein.
Hoisting of potash ore with saturated brine has been conducted to examine plugging of the hoist pipe (Shook, C A; Gillies, R G and Schergevitch, P J. Concentration Changes in Hydraulic Hoisting of Potash Ore. In: International Conference on Bulk Materials Storage, Handling and Transportation (4th: 1992: Wollongong, N. S. W.)).
Improved methods of hoisting potash, polyhalite and other evaporite ores from underground mines are desirable.
The preceding examples of the related art and limitations related to it are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a review of the drawings.